net/netfilter/nf_conntrack_proto_udplite.c

   1 /* (C) 1999-2001 Paul `Rusty' Russell
   2  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   3  * (C) 2007 Patrick McHardy <kaber@trash.net>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/timer.h>
  12 #include <linux/module.h>
  13 #include <linux/udp.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/ipv6.h>
  17 #include <net/ip6_checksum.h>
  18 #include <net/checksum.h>
  19
  20 #include <linux/netfilter.h>
  21 #include <linux/netfilter_ipv4.h>
  22 #include <linux/netfilter_ipv6.h>
  23 #include <net/netfilter/nf_conntrack_l4proto.h>
  24 #include <net/netfilter/nf_conntrack_ecache.h>
  25 #include <net/netfilter/nf_log.h>
  26
  27 enum udplite_conntrack {
  28         UDPLITE_CT_UNREPLIED,
  29         UDPLITE_CT_REPLIED,
  30         UDPLITE_CT_MAX
  31 };
  32
  33 static unsigned int udplite_timeouts[UDPLITE_CT_MAX] = {
  34         [UDPLITE_CT_UNREPLIED]  = 30*HZ,
  35         [UDPLITE_CT_REPLIED]    = 180*HZ,
  36 };
  37
  38 static int udplite_net_id __read_mostly;
  39 struct udplite_net {
  40         struct nf_proto_net pn;
  41         unsigned int timeouts[UDPLITE_CT_MAX];
  42 };
  43
  44 static inline struct udplite_net *udplite_pernet(struct net *net)
  45 {
  46         return net_generic(net, udplite_net_id);
  47 }
  48
  49 static bool udplite_pkt_to_tuple(const struct sk_buff *skb,
  50                                  unsigned int dataoff,
  51                                  struct net *net,
  52                                  struct nf_conntrack_tuple *tuple)
  53 {
  54         const struct udphdr *hp;
  55         struct udphdr _hdr;
  56
  57         /* Actually only need first 4 bytes to get ports. */
  58         hp = skb_header_pointer(skb, dataoff, 4, &_hdr);
  59         if (hp == NULL)
  60                 return false;
  61
  62         tuple->src.u.udp.port = hp->source;
  63         tuple->dst.u.udp.port = hp->dest;
  64         return true;
  65 }
  66
  67 static bool udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
  68                                  const struct nf_conntrack_tuple *orig)
  69 {
  70         tuple->src.u.udp.port = orig->dst.u.udp.port;
  71         tuple->dst.u.udp.port = orig->src.u.udp.port;
  72         return true;
  73 }
  74
  75 /* Print out the per-protocol part of the tuple. */
  76 static void udplite_print_tuple(struct seq_file *s,
  77                                 const struct nf_conntrack_tuple *tuple)
  78 {
  79         seq_printf(s, "sport=%hu dport=%hu ",
  80                    ntohs(tuple->src.u.udp.port),
  81                    ntohs(tuple->dst.u.udp.port));
  82 }
  83
  84 static unsigned int *udplite_get_timeouts(struct net *net)
  85 {
  86         return udplite_pernet(net)->timeouts;
  87 }
  88
  89 /* Returns verdict for packet, and may modify conntracktype */
  90 static int udplite_packet(struct nf_conn *ct,
  91                           const struct sk_buff *skb,
  92                           unsigned int dataoff,
  93                           enum ip_conntrack_info ctinfo,
  94                           u_int8_t pf,
  95                           unsigned int hooknum,
  96                           unsigned int *timeouts)
  97 {
  98         /* If we've seen traffic both ways, this is some kind of UDP
  99            stream.  Extend timeout. */
 100         if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 101                 nf_ct_refresh_acct(ct, ctinfo, skb,
 102                                    timeouts[UDPLITE_CT_REPLIED]);
 103                 /* Also, more likely to be important, and not a probe */
 104                 if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
 105                         nf_conntrack_event_cache(IPCT_ASSURED, ct);
 106         } else {
 107                 nf_ct_refresh_acct(ct, ctinfo, skb,
 108                                    timeouts[UDPLITE_CT_UNREPLIED]);
 109         }
 110         return NF_ACCEPT;
 111 }
 112
 113 /* Called when a new connection for this protocol found. */
 114 static bool udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
 115                         unsigned int dataoff, unsigned int *timeouts)
 116 {
 117         return true;
 118 }
 119
 120 static int udplite_error(struct net *net, struct nf_conn *tmpl,
 121                          struct sk_buff *skb,
 122                          unsigned int dataoff,
 123                          enum ip_conntrack_info *ctinfo,
 124                          u_int8_t pf,
 125                          unsigned int hooknum)
 126 {
 127         unsigned int udplen = skb->len - dataoff;
 128         const struct udphdr *hdr;
 129         struct udphdr _hdr;
 130         unsigned int cscov;
 131
 132         /* Header is too small? */
 133         hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 134         if (hdr == NULL) {
 135                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 136                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 137                                       "nf_ct_udplite: short packet ");
 138                 return -NF_ACCEPT;
 139         }
 140
 141         cscov = ntohs(hdr->len);
 142         if (cscov == 0)
 143                 cscov = udplen;
 144         else if (cscov < sizeof(*hdr) || cscov > udplen) {
 145                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 146                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 147                                 "nf_ct_udplite: invalid checksum coverage ");
 148                 return -NF_ACCEPT;
 149         }
 150
 151         /* UDPLITE mandates checksums */
 152         if (!hdr->check) {
 153                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 154                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 155                                       "nf_ct_udplite: checksum missing ");
 156                 return -NF_ACCEPT;
 157         }
 158
 159         /* Checksum invalid? Ignore. */
 160         if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 161             nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
 162                                 pf)) {
 163                 if (LOG_INVALID(net, IPPROTO_UDPLITE))
 164                         nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
 165                                       "nf_ct_udplite: bad UDPLite checksum ");
 166                 return -NF_ACCEPT;
 167         }
 168
 169         return NF_ACCEPT;
 170 }
 171
 172 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 173
 174 #include <linux/netfilter/nfnetlink.h>
 175 #include <linux/netfilter/nfnetlink_cttimeout.h>
 176
 177 static int udplite_timeout_nlattr_to_obj(struct nlattr *tb[],
 178                                          struct net *net, void *data)
 179 {
 180         unsigned int *timeouts = data;
 181         struct udplite_net *un = udplite_pernet(net);
 182
 183         /* set default timeouts for UDPlite. */
 184         timeouts[UDPLITE_CT_UNREPLIED] = un->timeouts[UDPLITE_CT_UNREPLIED];
 185         timeouts[UDPLITE_CT_REPLIED] = un->timeouts[UDPLITE_CT_REPLIED];
 186
 187         if (tb[CTA_TIMEOUT_UDPLITE_UNREPLIED]) {
 188                 timeouts[UDPLITE_CT_UNREPLIED] =
 189                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_UNREPLIED])) * HZ;
 190         }
 191         if (tb[CTA_TIMEOUT_UDPLITE_REPLIED]) {
 192                 timeouts[UDPLITE_CT_REPLIED] =
 193                   ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_REPLIED])) * HZ;
 194         }
 195         return 0;
 196 }
 197
 198 static int
 199 udplite_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 200 {
 201         const unsigned int *timeouts = data;
 202
 203         if (nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_UNREPLIED,
 204                          htonl(timeouts[UDPLITE_CT_UNREPLIED] / HZ)) ||
 205             nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_REPLIED,
 206                          htonl(timeouts[UDPLITE_CT_REPLIED] / HZ)))
 207                 goto nla_put_failure;
 208         return 0;
 209
 210 nla_put_failure:
 211         return -ENOSPC;
 212 }
 213
 214 static const struct nla_policy
 215 udplite_timeout_nla_policy[CTA_TIMEOUT_UDPLITE_MAX+1] = {
 216         [CTA_TIMEOUT_UDPLITE_UNREPLIED] = { .type = NLA_U32 },
 217         [CTA_TIMEOUT_UDPLITE_REPLIED]   = { .type = NLA_U32 },
 218 };
 219 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 220
 221 #ifdef CONFIG_SYSCTL
 222 static struct ctl_table udplite_sysctl_table[] = {
 223         {
 224                 .procname       = "nf_conntrack_udplite_timeout",
 225                 .maxlen         = sizeof(unsigned int),
 226                 .mode           = 0644,
 227                 .proc_handler   = proc_dointvec_jiffies,
 228         },
 229         {
 230                 .procname       = "nf_conntrack_udplite_timeout_stream",
 231                 .maxlen         = sizeof(unsigned int),
 232                 .mode           = 0644,
 233                 .proc_handler   = proc_dointvec_jiffies,
 234         },
 235         { }
 236 };
 237 #endif /* CONFIG_SYSCTL */
 238
 239 static int udplite_kmemdup_sysctl_table(struct nf_proto_net *pn,
 240                                         struct udplite_net *un)
 241 {
 242 #ifdef CONFIG_SYSCTL
 243         if (pn->ctl_table)
 244                 return 0;
 245
 246         pn->ctl_table = kmemdup(udplite_sysctl_table,
 247                                 sizeof(udplite_sysctl_table),
 248                                 GFP_KERNEL);
 249         if (!pn->ctl_table)
 250                 return -ENOMEM;
 251
 252         pn->ctl_table[0].data = &un->timeouts[UDPLITE_CT_UNREPLIED];
 253         pn->ctl_table[1].data = &un->timeouts[UDPLITE_CT_REPLIED];
 254 #endif
 255         return 0;
 256 }
 257
 258 static int udplite_init_net(struct net *net, u_int16_t proto)
 259 {
 260         struct udplite_net *un = udplite_pernet(net);
 261         struct nf_proto_net *pn = &un->pn;
 262
 263         if (!pn->users) {
 264                 int i;
 265
 266                 for (i = 0 ; i < UDPLITE_CT_MAX; i++)
 267                         un->timeouts[i] = udplite_timeouts[i];
 268         }
 269
 270         return udplite_kmemdup_sysctl_table(pn, un);
 271 }
 272
 273 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
 274 {
 275         .l3proto                = PF_INET,
 276         .l4proto                = IPPROTO_UDPLITE,
 277         .name                   = "udplite",
 278         .allow_clash            = true,
 279         .pkt_to_tuple           = udplite_pkt_to_tuple,
 280         .invert_tuple           = udplite_invert_tuple,
 281         .print_tuple            = udplite_print_tuple,
 282         .packet                 = udplite_packet,
 283         .get_timeouts           = udplite_get_timeouts,
 284         .new                    = udplite_new,
 285         .error                  = udplite_error,
 286 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 287         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 288         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 289         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 290         .nla_policy             = nf_ct_port_nla_policy,
 291 #endif
 292 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 293         .ctnl_timeout           = {
 294                 .nlattr_to_obj  = udplite_timeout_nlattr_to_obj,
 295                 .obj_to_nlattr  = udplite_timeout_obj_to_nlattr,
 296                 .nlattr_max     = CTA_TIMEOUT_UDPLITE_MAX,
 297                 .obj_size       = sizeof(unsigned int) *
 298                                         CTA_TIMEOUT_UDPLITE_MAX,
 299                 .nla_policy     = udplite_timeout_nla_policy,
 300         },
 301 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 302         .net_id                 = &udplite_net_id,
 303         .init_net               = udplite_init_net,
 304 };
 305
 306 static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
 307 {
 308         .l3proto                = PF_INET6,
 309         .l4proto                = IPPROTO_UDPLITE,
 310         .name                   = "udplite",
 311         .allow_clash            = true,
 312         .pkt_to_tuple           = udplite_pkt_to_tuple,
 313         .invert_tuple           = udplite_invert_tuple,
 314         .print_tuple            = udplite_print_tuple,
 315         .packet                 = udplite_packet,
 316         .get_timeouts           = udplite_get_timeouts,
 317         .new                    = udplite_new,
 318         .error                  = udplite_error,
 319 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 320         .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
 321         .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
 322         .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
 323         .nla_policy             = nf_ct_port_nla_policy,
 324 #endif
 325 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
 326         .ctnl_timeout           = {
 327                 .nlattr_to_obj  = udplite_timeout_nlattr_to_obj,
 328                 .obj_to_nlattr  = udplite_timeout_obj_to_nlattr,
 329                 .nlattr_max     = CTA_TIMEOUT_UDPLITE_MAX,
 330                 .obj_size       = sizeof(unsigned int) *
 331                                         CTA_TIMEOUT_UDPLITE_MAX,
 332                 .nla_policy     = udplite_timeout_nla_policy,
 333         },
 334 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 335         .net_id                 = &udplite_net_id,
 336         .init_net               = udplite_init_net,
 337 };
 338
 339 static int udplite_net_init(struct net *net)
 340 {
 341         int ret = 0;
 342
 343         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udplite4);
 344         if (ret < 0) {
 345                 pr_err("nf_conntrack_udplite4: pernet registration failed.\n");
 346                 goto out;
 347         }
 348         ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udplite6);
 349         if (ret < 0) {
 350                 pr_err("nf_conntrack_udplite6: pernet registration failed.\n");
 351                 goto cleanup_udplite4;
 352         }
 353         return 0;
 354
 355 cleanup_udplite4:
 356         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite4);
 357 out:
 358         return ret;
 359 }
 360
 361 static void udplite_net_exit(struct net *net)
 362 {
 363         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite6);
 364         nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite4);
 365 }
 366
 367 static struct pernet_operations udplite_net_ops = {
 368         .init = udplite_net_init,
 369         .exit = udplite_net_exit,
 370         .id   = &udplite_net_id,
 371         .size = sizeof(struct udplite_net),
 372 };
 373
 374 static int __init nf_conntrack_proto_udplite_init(void)
 375 {
 376         int ret;
 377
 378         ret = register_pernet_subsys(&udplite_net_ops);
 379         if (ret < 0)
 380                 goto out_pernet;
 381
 382         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udplite4);
 383         if (ret < 0)
 384                 goto out_udplite4;
 385
 386         ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udplite6);
 387         if (ret < 0)
 388                 goto out_udplite6;
 389
 390         return 0;
 391 out_udplite6:
 392         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
 393 out_udplite4:
 394         unregister_pernet_subsys(&udplite_net_ops);
 395 out_pernet:
 396         return ret;
 397 }
 398
 399 static void __exit nf_conntrack_proto_udplite_exit(void)
 400 {
 401         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
 402         nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
 403         unregister_pernet_subsys(&udplite_net_ops);
 404 }
 405
 406 module_init(nf_conntrack_proto_udplite_init);
 407 module_exit(nf_conntrack_proto_udplite_exit);
 408
 409 MODULE_LICENSE("GPL");